Technical Field
The invention relates to an optical device and a display apparatus having the optical device, and particularly relates to a wavelength conversion device and a projector using the wavelength conversion device.
Related Art
In recent years, projectors using solid-state light sources such as light-emitting diodes (LEDs) and laser diodes gradually occupy a space in the market. Since the LEDs have light efficiency of higher than 20%, in order to break through a light source limitation of the LED, a technique of using a laser light source to excite phosphor powder to produce a pure color light source required by the projector is gradually developed. Moreover, besides using the laser light source to excite the phosphor powder to emit light, the laser projector also directly uses the laser light source to serve as an illumination light source, and the laser projector is capable of adjusting the number of the light sources according to a brightness requirement, so as to achieve different brightness requirements of the projectors. Therefore, the laser light source used by a light source system of the projector structure has a great potential to replace the conventional high pressure mercury lamp to become light sources of mainstream projectors of a new generation.
In a present laser projector, the phosphor powder is generally coated on a metal substrate with a high reflectivity to form a phosphor wheel, and the phosphor powder on the metal substrate is excited by the laser light emitted by the laser light source to generate lights with different colors (for example, a green light and a yellow light), and the laser light (for example, a blue light) directly passes through the phosphor wheel through a hollow slot on the metal substrate, so as to generate lights of various colors. Under such design, when the metal substrate rotates, an airborne noise is generated due to configuration of the hollow slot. Moreover, in order to avoid asymmetric structure of the metal substrate caused by the hollow slot to cause excessive wobble of the metal substrate during rotation of the metal substrate, some metal substrates of the phosphor wheel are added with another hollow slot to symmetrize the structure of the metal substrate, though such method aggravates the airborne noise, and a heat dissipation area of the metal substrate is decreased to degrade a heat dissipation efficiency of the phosphor wheel.
U.S. Pat. No. 8,157,398 discloses a light radiation wheel applied to a projector, the light radiation wheel includes an opaque substrate and a transparent diffusion substrate adjacent to each other, a blue excitation beam emitted by a light emitter excites the phosphor powder on the opaque substrate or directly penetrates through the diffusion substrate. U.S. Patent Publication No. 20090273763 discloses a color wheel, on which one end of a filter sheet is fixed between a protruding spring and a protruding board of the color wheel. U.S. Pat. No. 6,963,457 discloses a color wheel, in which a center portion of one block thereof has a plurality of indentations for fitting the other blocks of the color wheel.
The information disclosed in this “BACKGROUND” section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in this “BACKGROUND” section does not mean that one or more problems to be solved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.